The anchor, 51, expects to take a medical leave in late August or early September from her morning show, which has reigned over Today for the past four weeks, to undergo a bone-marrow transplant.

"It's fascinating-slash-scary how to prepare yourself for something like this," Roberts told reporters gathered for the Television Critics Association conference in Beverly Hills, Calif., via satellite from ABC's studios in New York, according to New York's Daily News.

Roberts – who revealed she was batting the rare disease of the blood and bone marrow in June with the subsequent news that her sister would donate bone marrow – says she feels "moments of fatigue" lately, although her job has helped her pull through.

"The [ratings] run that we've had has truly energized me," said Roberts, who successfully battled breast cancer five years ago. "It's pretty good medicine – I gotta say."

Filling in through her absence, reports the Daily News, quoting possibilities provided by ABC News president Ben Sherwood: such familiar faces as Barbara Walters, Diane Sawyer, Katie Couric, Kelly Ripa and the cast of The View.